Method and packer for processing a productive formation in bottom-hole zone of a well, and method for fixing a packer inside a well

ABSTRACT

The proposed method for processing the productive formation in a bottom-hole zone of a well ( 1 ) comprises heating the liquid in the bottom-hole zone of a well ( 1 ) and removing clogging products therefrom. In accordance with the technical solution, the upper part of the bottom-hole zone of the well ( 1 ) is sealed before heating the liquid, thus forming a bottom-hole chamber ( 6 ), and after the heating, the liquid within the volume of the bottom-hole chamber ( 6 ) is cooled and then this chamber ( 6 ) is unsealed before removing the clogging products therefrom.  
     In the proposed packer ( 4 ) for processing the productive formation in the bottom-hole zone of a well ( 1 ), comprising a body ( 10 ) with a means for radial compaction in the form of sliding cheeks, a cup-type seal ( 15 ) and a drive, and a suspension means ( 2 ), in accordance with the technical solution, the lower end face ( 5 ) is made in the form of a concave surface of the second order.  
     A method for fixing a packer ( 4 ) in a well ( 1 ), comprising lowering it into the well ( 1 ) to a required depth, increasing the diametral size of the packer ( 4 ) and deforming its cup-type seal ( 15 ) in a radial direction, wherein in accordance with the technical solution, the packer ( 4 ) is subjected to temperature action different from the temperature of the well liquid at the point of its installation. 19 dependent claims, 15 drawings.

FIELD OF THE INVENTION

[0001] The proposed invention relates to the oil producing industry andhas the purpose of increasing the productivity of a well by intensifyingthe flow of oil and increasing the oil recovery factor, and also servesfor major repair of wells, for cutting-off water-encroached formations,etc.

BACKGROUND ART

[0002] A method is known for electrically heating a bottom-hole zone(see, e.g., A.A. Popov. Impact action on bottom-hole zone. Moscow,“Nedra,”1990, pp. 36-38). This method consists in that the liquid in thebottom-hole zone is heated to about 100° C., which ensures a reductionof the viscosity of paraffin-base and high-viscosity crude oils of, forexample, the Usinsky and Kharyachinslky fields. As a result the oilrecovery from the wells is increased.

[0003] The main drawback of the foregoing method is that it is onlypossible to use it in a narrow field - during the production ofhigh-viscosity and paraffin-base crude oils, when paraffins resins andasphaltenes precipitate into the bottom-hole zone. Furthermore, thedescribed method is complex in the practical realization thereof, sincethe electric heaters often break down because of the poor quality of thecable and the heating elements, which work in an aggressive medium.

[0004] A method for thermal treatment of the bottom-hole zone of an oilformation is also known according to USSR Inventor's Certificate No.467173, class E 21 B 43/24,published in BI No. 14, 1975. This methodconsists in providing thermal treatment to the bottom-hole zone bypumping a heat carrier with high thermal conductivity into theformation. Granulated material, for example, metal powder, is used asthe heat carrier. The granulometric composition of the metal powders isselected on the basis of considerations relating to their being pumpedin and also to their capability of penetrating into cracks of theformation. A source of thermal-gas or thermal-gas-chemical action, theplane of the start of combustion of which is positioned below the lowerperforations of the interval being processed by 5-15% of its length, isused as the slowly-burning source of thermal action, and afteraccumulating heat in the processed interval, movement of the downholetechnological equipment with the source of thermal-gas orthermal-gas-chemical action is carried out along the interval beingprocessed, after which a technological delay is carried out tosubstitute the gaseous combustion products in the interval beingprocessed with well liquid. The prepared suspensions do not penetrateinto pore channels, but fill the formation cracks in the bottom-holezone, which are present and open up in the process of pumping. After asystem of cracks, filled with granulated metal powder, is created in theformation, an electrical heating device is lowered into the well and thebottom-hole zone is heated.

[0005] The method is also complex in realization, since actually it is atwo-step method, i.e. at first hydraulic fracturing is effected, andthen metal powders are pumped into the cracks. Its relatively loweffectiveness is predetermined by the fact that in order for the metalpowder to penetrate into the formed cracks, small forces, occurring as aresult of the volumetric expansion during the heating of the bottom-holeliquid, are used, and therefore the heating spreads into the depth ofthe formation to only a small distance.

[0006] A method of fracturing a formation is known, the methodcomprising creating cracks by fracturing the formation with explosivegases and fixing the cracks by pumping a liquid with a solid agent, forexample, silica sand, into the formation with a pump (see, for example,Yu.M. Zheltov. Deformation of rocks. Moscow, “Nedra,” 1966).

[0007] A drawback of this method is the high amount of labor consumedand the cost, which is related to the use of pumps.

[0008] A method of fracturing a formation with explosive gases is alsoknown from U.S. Pat. No. 3,422,760, class 102-21.6. This methodcomprises creating cracks by the pressure of gases which are producedduring the combustion in the well of an explosive charge positionedopposite the productive formation. A drawback of this method is that theexplosive gases are only partially used to create cracks in thebottom-hole zone, a part thereof (about 50%) goes up through the well,wherewith the cable to which the charge is suspended twists, and thispredetermines the necessity for its subsequent extraction. This laststep is rather complex, is often related to the necessity of cutting thecable and extracting separate pieces thereof with catchers. Sometimes,it is not possible to extract all the pieces of the cut cable and thewell has to be abandoned.

[0009] A method of processing the zone of a productive formation in theregion of the bottom with the use of implosion is also known (see, forexample. A.A. Popov. Impact actions on bottom-hole zone. Moscow,“Nedra,” 1990, pp. 35-36). The substance of this method is that a hollowvessel with a membrane is arranged on a tubing string opposite theinterval of the formation being processed. Then this membrane isfractured, as a result of which rarefaction is created in the bottomhole. Due to the occurrence of depression of the pressure, the formationliquid enters the well at high speed. The intensive movement of theformation liquid into the well promotes the cleansing of the part of theformation being filtered of deposits.

[0010] An analysis of the available results of processing bottom-holezones with the use of implosions at the Zapadno-Tebuksk, Nizhneomrinskyand lzhma-Omrinsky oil fields has shown that this method has limited usein respect to mining and geological conditions. It is of loweffectiveness at high permeability of the bottom-hole zone, since thespeed of the flow of formation liquid from the productive formation intothe well is low because of the large size of the pores and cracks in thebottom-hole zone.

[0011] Furthermore, there were cases where the use of implosions did notprovide the desired result because the membranes, produced from greyiron SSH15-32, fractured before they were supposed to. This reduces therange of use of the method with implosions and its effectiveness, andwherewith, a positive result is not achieved in all cases when thismethod is used.

[0012] The analog most similar to the proposed method in respect totechnical essence and attained effect is the method for processing thebottom-hole zone according to patent RF No. 2087693, class E21 B 43/25,published in BI No. 23, 1997. This latter method comprises loweringdownhole technological equipment with a charge of a slowly burningsource of thermal action, burning the latter in an interval beingprocessed, carrying out a technological delay to accumulate heat in theinterval being processed, providing depression action and removing apart of the well liquid with clogging elements which entered it from thebottom-hole zone during the depression action. Wherein, a slowly-burningsource of thermal action is used, the plane of the beginning ofcombustion of which is positioned below the lower perforations of theinternal being processed by 5-10% of its length, and after accumulatingheat in the interval being processed, the downhole technologicalequipment with the source of thermal-gas-chemical action is moved alongthe interval being processed, after which there is a technological delayto substitute gaseous combustion products in the interval beingprocessed with well liquid.

[0013] Drawbacks of this method are: a) the difficulty ofimplementation, related to movement of the equipment along the intervalbeing processed; b) the length of the process, related to movement ofthe equipment and the technological delays in order to replace thegaseous combustion products in the interval being processed with wellliquid; c) small distances from the well walls on which thehigh-temperature zone acts (it is because of this reason in particularthat it is necessary to move the equipment with the source of thermalaction along the well). All these drawbacks reduce the effectiveness ofuse of this method.

[0014] A packer is known in accordance with USSR Inventor's CertificateNo. 1099047, class E21 B 33/12, published in BI No. 23, 1984. Thispacker comprises a hollow body with radial channels, on which body aseal element with a cavity for its drive is mounted, a shaft arranged inthe body with the possibility for axial movement and coupled to astring, the shaft being hollow, sealed in the lower part, with two rowsof radial channels to couple the intratube space accordingly with theannulus above-packer space and the cavity of the seal element drive.Wherein the packer is provided with a housing with radial channels,which is mounted above the seal element and forms with the body achamber in which a spring-loaded choke bean is mounted, and the annulusabove-packer space is coupled to the intratube space via the channel ofthe choke bean.

[0015] Drawbacks of the known packer are the complexity of its structureand, in view of this, low operational reliability, since clogging of thechannel “A” of the hydraulic resistance and the openings, communicatingits inner cavity with the upper, and the upper and lower chambers, withparticles found in the well liquid, is not eliminated. The packer underconsideration seals the cross section of the well, preventing movementof the flow in any direction. A packer of such a construction cannot beused in the case where it is necessary to provide for flow of the wellliquid in one direction only.

[0016] An interval packer is known according to USSR Inventor'sCertificate No. 643625, class E21 B 33/12, published in BI No. 3, 1979.This packer comprises upper and lower packers with shafts made withradial channels, a body with windows, an anchor, a valve device, caseand catch, wherein the shaft of the lower packer is rigidly connected tothe case, and the catch is mounted at the end of the shaft of the upperpacker with the possibility for interaction with the case, wherein inthe lower part of the shaft of the lower packer a branch pipe is rigidlyconnected thereto, the branch pipe forming with the shaft an annularcavity, and a piston is mounted under a sealing element, the pistonforming with the shaft a chamber communicating with the annular cavity,and during packing - with the intrapacker space. The construction of thepacker is designed to cut off the flow of liquid and it cannot be usedto provide passage of the flow of well liquid in one direction only.

[0017] A packer according to USSR Inventor's Certificate No. 304345,class E 21 B 33/12, published in BI No. 17, 1971, is also known. Thispacker comprises a body with radial channels, sealing elements withslips, a housing and fixing unit with spring-loaded slips interactingwith pushers and a toothed surface of a branch pipe. A piston, rigidlyconnected to pushers, is positioned concentrically between the body andthe housing, and the under-piston cavity communicates with an intrapipespace.

[0018] A drawback of the known packer is the low reliability of itsoperation because of the possible clogging of channels “a” and “b” andcavities “A” and “B” with particles which are in the well liquid.Furthermore, the cross section of the central channel of the packer issharply reduced because of the concentrically positioned body, annularpiston and housing.

[0019] A well fixing apparatus according to USSR Inventor's CertificateNo. 1122817, class E21 B 47/00, published in BI No. 41, 1984, is alsoknown. This apparatus comprises a body, a cable, a bushing, a stoppingdevice, a tightening mechanism coupled to a spacer element provided witha parachute of elastic material stretched on a frame of levershinge-connected to the bushing, and a resilient element, an additionalspring, additional supports, a stopping bushing with inner supports andwith a ring-catch, lower levers, wherein the additional spring isarranged inside the stopping bushing mounted in the lower part of thebody, spring-loading the bushing relative to the body, and interactswith the tightening mechanism, and the additional supports are mountedon the lower levers, hinge connected to the resilient element. The lowerend face thereof is made in the form of a cone.

[0020] A drawback of the fixing apparatus being considered is theineffectiveness of its use during an explosion, since the gases producedthereby will promote unsealing of the well.

[0021] The analog most similar in respect to technical essence andattained effect is the hydraulic packer for a formation tester accordingto USSR Inventor's Certificate No. 571581, class E21 B 33/12, publishedin BI No. 33, 1977. This packer comprises a rod, a hydraulic pump and anelastic cup with a springy support made of inner and outer rows ofplates shifted relative to one another. Wherewith, the inner plates areprovided with end pieces which are placed in the elastic cup and rigidlyconnected to the plates of the outer row. The lower surface of thepacker is made flat, passing into a conical surface, then again into aflat and conical, which form with the wall of the well a wedge “pocket.”

[0022] A drawback of the packer under consideration is that its use isnot possible in order to provide flow of the well liquid in onedirection only, since it completely seals the flow cross section of thewell. Furthermore, a drawback of the packer is its low reliability, thisbeing related to the possibility of channel “a” and the inner cavity ofthe elastic cup being clogged with particles which are in the wellliquid.

[0023] A method for fixing a packer in a well is known, this methodbeing realized in the construction of the packer according to USSRInventor's Certificate No. 252244, class E21 B, published in BI No. 29,1969, and consisting in that the sealing elements of the packer areunwedged, moving one part thereof relative to another, wherein thetapered elements of the packer, which have tapered surfaces, are moved(in the longitudinal section two neighboring elements have an inclinedsurface, and each element is made in the form a triangle, wherein one ofthe bases of neighboring elements faces the wall of the well, the otherfaces the longitudinal axis thereof). In order to extract the packer itis pulled upwards, thereby cutting off the pins and thus reducing itscross section.

[0024] A drawback of this method is the difficulty of extracting apacker of such a construction because of the large diametricaldimensions, since tapered sections are used which move one on top ofanother, as a result of which the packer occupies greater space in thecross section. During the unwedging it is not possible to substantiallyreduce its cross section in order to reliably extract it from the well.

[0025] A method for fixing a packer in a well is also known, this methodbeing realized in the hydraulic packer according to USSR Inventor'sCertificate No. 571581, class E21 B 33/12, published in BI No. 33, 1977,and consisting in that an elastic cup is spread apart in a radialdirection by applying drilling fluid under pressure into the innercavity of the elastic cup. A piston and hydraulic pump are used tocreate pressure. In order to extract the packer, the pressure is turnedoff and by moving the piston to the upper position the elastic cup isreturned to its initial position by springs especially serving thispurpose.

[0026] A drawback of the described method is the necessity of using twodrives to fix the packer to the wall of the well and to separate ittherefrom, and this makes the construction of the packer and control ofits operation more complex.

[0027] A method for fixing a packer, realized in a packing deviceaccording to USSR Inventor's Certificate No. 898043, class E21 B{fraction (33/12)}, published in BI No. 2, 1982, is known. This methodcomprises changing the radial dimension of a sealing element of thepacking device by mechanical axial action on it, wherewith this actionis carried out in two steps, in particular: at first the lower part ofthe packing device is set in the bottom hole of the well, moving one ofits parts relative to another in an axial direction, and thencontraction is created by hydraulic pressure.

[0028] A drawback of the known method is that it is not possible tomount the packing device high above the well bottom. Furthermore, theuse of two drives for fixing and separating predetermines complexity ofthe construction of the packing device and complexity of its control.

[0029] The analog most similar in respect to technical essence andattained effect is the method for fixing a packer in a well, which isrealized in the packer according to USSR Inventor's Certificate No.304345, class E21 B {fraction (33/12)}, published in BI No. 17, 1971,and consists in radial deformation of an annular packer seal as a resultof its axial compression by the hydraulic pressure of liquid pumped intothe well.

[0030] A drawback of the known method is that it does not ensurereliability of operation of the packer, this being related to thenecessity for a constant supply of well liquid under pressure, whichfinally results in clogging of the working chamber of the packer, whichvia the moving piston supplies the hydraulic pressure of the liquid tothe sealing elements of the packer.

Disclosure Of The Invention

[0031] The technical object of the proposed invention is to enhance theeffectiveness of oil inflow, and consequently, enhance the productivityof the well by removing the clogging products from the bottom-hole zone,and to simplify the technology of processing the bottom-hole zone byremoving the clogging products from the bottom-hole zone of the well inone step and to eliminate destruction of the packer suspension means.Furthermore, the construction of the packer is simplified and thereliability of its fixation in the well is enhanced by temperatureaction and additional tightness between the surfaces of the packer andthe well.

[0032] This object is achieved in a method for processing the productiveformation in a bottom-hole zone of a well, comprising heating liquid inthe bottom-hole zone and removing clogging products from the bottom-holezone, in that in accordance with the technical solution, prior toheating the liquid, the bottom-hole zone of the well is sealed in theupper part, forming thereby a bottom-hole chamber, and after heating,the liquid is cooled in the volume of the bottom-hole chamber and thenthis chamber is unsealed prior to removing the clogging productstherefrom.

[0033] These steps and their sequence ensure a liquid flow at first inthe direction of the formation due to volumetric expansion of the liquidin the bottom-hole chamber, and then in the reverse direction from theformation due to depression, which ensures the simultaneous expansion ofcracks in the bottom-hole zone as a result of the produced flow, andconsequently, pressure of the liquid, and also reduction of theviscosity of the oil and removal of asphalt-resin-paraffin deposits bytemperature action (the known effect of temperature action). The reverseflow of liquid from the formation into the bottom-hole chamber promotespurification of the filtered part of the formation of deposits and incertain cases results in breakage of the rock in the bottom-hole zone ofthe well and the formation of additional cracks there. This, finally,enhances the productivity of the well and simplifies technology, sincecases of twisting the cable in the well because of the presence of theparker are eliminated, and this means that steps in respect to cuttingit and extracting separate pieces of the cable with catchers areeliminated.

[0034] It is advisable that the liquid in the bottom-hole chamber beheated to a temperature above the boiling point of one of the light oilfractions, e.g. gasoline.

[0035] Such a step ensures the transition of light oil fractions intovapors. (The boiling point is 80-96° C. Here and below consideration isgiven to normal pressure in view of the fact that the pressure in theliquid in the bottom-hole zone depends on the depth of the well. In viewof this, the boiling point of water and the fractions increases,remaining however different one from the other, i.e. for a concretewell, their boiling points should be calculated in accordance with theweight of the column of liquid in the well.) The liquid in thebottom-hole chamber increases its volume to a greater degree and this ispromoted by the vapor into which one of the components of the lightfractions of oil has passed. As a result, the pressure in thebottom-hole chamber is sharply increased and, as a consequence thereof,the effectiveness of the oil inflow is increased, since at higherpressure its action is effected at a greater distance from the well andthe depression effect will also be large.

[0036] It is advisable that the liquid in the bottom-hole chamber beheated to a temperature above the boiling point of water.

[0037] Such a step makes it possible to enhance the effectiveness of theprocess of processing the bottom-hole zone of the well, since theboiling point of water is above the boiling point of the light oilfractions (respectively 100° C. and 80-96° C. at normal pressure).Therefore, there is a transition of water and the light oil fractionsinto vapor, and, consequently, the partial pressure of the liquidcomponents in the bottom-hole chamber which pass into vapor will beadded up and the resultant pressure becomes greater than the partialpressure of one of the liquid components which have passed into vapor.

[0038] It is advisable that the liquid in the bottom-hole zone be heatedto a temperature above the boiling point of one of the heavy oilfractions, e.g., oils. This step even more enhances the effectiveness ofthe proposed method, since a large number of the liquid components inthe bottom-hole chamber pass into vapor (the boiling point of oils is460-500° C. at normal pressure), consequently, the total pressure in thebottom-hole chamber increases in accordance with the Dalton Law. Theeffectiveness of the action of pressure in the bottom-hole chamber alsoincreases, that is it will act on the particles deposited in the poresof the bottom-hole zone at a greater distance from the walls of thewell. The permeability of the bottom-hole zone of the productiveformation is enhanced by the simultaneous action of the pressure andtemperature created in the bottom-hole chamber.

[0039] It is advisable that the liquid in the bottom-hole chamber beheated instantly, e.g., by an explosion. The effects described abovewill be manifested to an even greater degree, since the produced vaporswhich are in the bottom-hole chamber do not have time to partially fallinto the liquid and into the productive formation, which is observedduring slow heating, as a result of which increased pressure will be inthe bottom-hole chamber, and consequently, the action of pressure willoccur at a greater distance from the well.

[0040] It is advisable that cooling the liquid within the volume of thebottom-hole zone of the well be carried out in a forced manner with theuse of special means, for example, thermocouples.

[0041] Such an operation intensifies the flow of liquid from theproductive formation into the well, which makes it possible to firstremove the clogging products from the bottom-hole zone of the well andthen to increase the oil production rate.

[0042] It is advisable that after the formation of the bottom-holechamber, the column of well liquid therein be divided into two parts,one of which directed to the bottom-hole zone of the well, the otherremoved through the packer, and that movement of the well liquid throughthe packer in the opposite direction be closed.

[0043] These operations and their sequence make it possible to carry outhydraulic fracturing in the bottom-hole zone of the well andsimultaneously to create depression of the pressure in the bottom-holechamber by removing well liquid from that chamber, which ensures a backflow of liquid from the formation into the well after the hydraulicfracturing, and this makes it possible to wash the cracks and pores inthe bottom-hole zone of the well, thereby removing the cloggingproducts. Finally, these operations make it possible to increase theinflow of formation liquid, which increases the effectiveness of oilinflow, and consequently to increase the productivity of operating thewell.

[0044] It is advisable after removal of a part of the column of wellliquid from the bottom-hole chamber through the packer to reduce thepressure in the upper part thereof and simultaneously to fill thebottom-hole chamber with formation liquid.

[0045] This makes it possible to increase the intensity of the inflow offormation liquid into the well, which enhances the washing of the cracksand pores in the bottom-hole zone of the well, and, consequently,improves the removal of clogging products.

[0046] In a packer for processing the productive formation in thebottom-hole zone of a well, comprising a body with a means for radialcompaction in the form of sliding cheeks, a cup-type seal and a drive,and a suspension means, in accordance with the technical solution, thelower end face is made in the form of a concave surface of the secondorder.

[0047] Such a construction of the packer is less subject to the negativeactions of an explosion, in particular, the absence of “pockets”eliminates unsealing of the packer (moreover, improves the sealing),and, being a reflector, directs the explosive wave along the axis of thewell in the direction of the productive formation, which improves theeffectiveness of processing the productive formation in the bottom-holezone of the well.

[0048] It is advisable that the concave surface of the second order inthe packer be made hemispherical.

[0049] Such a construction of the packer is the simplest in productionand during an explosion, by directing the explosive wave along thelongitudinal axis of the well, ensures its self-compaction.

[0050] It is advisable that the concave surface of the second order inthe packer be made paraboloidal.

[0051] Such a construction of the packer enhances the effectiveness ofits self-compaction and the directivity of the explosive wave along thelongitudinal axis of the well, since the lower end face surface of thepacker at the wall of the well has great length and more graduallypasses into a cylindrical surface.

[0052] It is advisable in these cases that the packer be made with atleast one channel connecting its end faces and be provided with aback-pressure valve, eliminating movement of the well liquid in thedirection to the bottom-hole chamber from the above-packer space of thewell.

[0053] Such a construction of the packer provides for realization of theproposed method for processing the productive formation in thebottom-hole zone of a well, i.e., the effective removal of a part of thewell liquid from the bottom-hole chamber with subsequent depression ofthe pressure therein by removal of the clogging products.

[0054] It is advisable that the packer be provided with atemperature-action element. Such a construction of the packer providesfor temperature action (heating or cooling) on its elements, which makesit possible to increase or reduce the diametral size of the packercup-type seal, ensuring fixation of the packer to the wall of the well(or its separation therefrom).

[0055] It is advisable that the temperature-action element of the packerbe made in the form of a pyrotechnic cartridge. Such a construction ofthe packer provides one-time heating of its structural elements, whichpredetermines the possibility for minimization of the energy necessaryto heat them.

[0056] It is advisable that the temperature-action element of the packerbe made in the form of an electric spiral connected to a power supply.Such a construction of the packer is as simple to produce as possibleand makes it possible to heat the elements of the packer construction amultiple number of times.

[0057] It is advisable that the temperature-action element of the packerbe made in the form of a cooling thermocouple. Such a construction ofthe packer eliminates the necessity for a constant supply of energyduring its fixation to the wall of the well (the energy is used onlyduring its extraction from the well or during its installation in thewell).

[0058] It is also advisable that the sliding cheeks of the packer bemade of a material with shape memory. Such a construction increases thereliability of packer operation, since it ensures reliability of itsfixation, independent of the diameter of the well and the cup-shapedpacker seal, which is made with a certain exactness and may change itssize under the effect of wear. Furthermore, the diameter of the well hasa different magnitude at different points of the depth.

[0059] In this case it is advisable that the sliding cheeks of thepacker be made in the form of a cylinder with longitudinal slots, endingwith openings, wherewith the longitudinal parts of the cylinder betweenthe slots be made in the form of lobes. Such a packer, having a simpleconstruction, provides reliable fixation to the wall of a well andseparation therefrom, and also free extraction from the well.

[0060] In a method for fixing the packer in a well, comprising loweringit into the well to the required depth, increasing the diametral size ofthe packer and deforming its cup-type seal in the radial direction, inaccordance with the technical solution, the packer is subjected totemperature action, different from the temperature of the well liquid atthe point of installation of the packer. Such a combination of stepsenhances the reliability of fixing the packer to the wall of the welland simultaneously makes it possible to simplify its construction, sincethe movable parts are removed therefrom and there is one drive to fixthe packer to the wall of the well and to separate it therefrom.

[0061] It is advisable that the temperature action on the packer becarried out by increasing the temperature to a temperature above thetemperature of the well liquid in the place where the packer isinstalled after it has been lowered to the required depth. This makes itpossible to control the process of fixing the packer in the wellindependent of its depth (the temperature of the well liquid depends onthe depth of the well). Furthermore, the possibility appears forenhancing the reliability of operation of the packers of knownconstructions by use of additional tightness created on the contactingsurfaces of the cup-type seal and the well when the packer is equippedwith a heating element.

[0062] It is advisable that the temperature action on the packer becarried by reducing the temperature to a temperature below thetemperature of the well liquid at the place where the packer isinstalled prior to its being lowered to the required depth. Theintroduction of such a step makes it possible to provide fixation of thepacker for a lengthy period of time without consumption of additionalenergy, since the fixation is accomplished by the temperature of thewell liquid.

[0063] It is advisable after the temperature action on the packer at theplace of its installation in the well at the required depth to carry outits temperature relief. The introduction of such a step enhances thereliability of extracting the packer from the well, since its diametralsize is reduced, which ensures its free extraction from the well.

BRIEF DESCRIPTION OF THE DRAWING

[0064] The substance of the proposed method for processing a productiveformation in the bottom-hole zone of a well, a packer for carrying outthe method and a method for fixing the packer in the well is explainedby an example of their use and by drawings.

[0065] The presented drawings show the following.

[0066]FIG. 1 shows the steps for installing a heating element in a well;

[0067]FIG. 2 shows sealing of the upper part of the bottom-hole zone ofa well;

[0068]FIG. 3 shows heating the liquid in the bottom-hole chamber andcreating a flow of liquid moving toward the formation;

[0069]FIG. 4 shows an explosion in the bottom-hole chamber;

[0070]FIG. 5 shows the step of cooling the liquid in the bottom-holechamber and forming a reverse flow of liquid as a result of depression;

[0071]FIG. 6 shows unsealing of the well;

[0072]FIG. 7 shows a packer arranged in the well;

[0073]FIG. 8 shows the installation of a packer in the well and theformation of a bottom-hole chamber;

[0074]FIG. 9 shows the division of a column of well liquid in thebottom-hole chamber and the removal of well liquid therefrom towards theproductive formation and through the packer;

[0075]FIG. 10 shows the bottom-hole chamber purified of well liquid anddepression of the pressure created;

[0076]FIG. 11 shows the filling of the bottom-hole chamber withformation liquid;

[0077]FIG. 12 shows the step of installing the packer in a casing;

[0078]FIG. 13 shows the step of thermal action on the packer (heating)and its fixation in the casing;

[0079]FIG. 14 shows a packer made of a material with a shape memory andwith a cooling thermocouple installed in the well;

[0080]FIG. 15 shows a packer made of a material with a shape memory,fixed in a well.

BEST VARIANT OF CARRYING OUT THE INVENTION

[0081] Realization of the proposed methods and packer is carried out inthe following sequence.

[0082] Using a suspension means (cable or pipe) 2, a heating element 3(FIG. 1) is lowered into the bottom-hole zone of a well (casing) 1. Theheating element 3 may be of any construction and its principle of actionmay be based on any physical or chemical effect. Thus, for example, aslowly burning source of thermal-gas-chemical action in the form of aEPIU-98-850 pyrotechnic charge with the following characteristics may beused: length 850 mm, diameter - 98 mm, weight - 7.5 kg; components -fuel 54%, oxidant 40%, technological additives 6%; density - 1.83 g/cm³;combustion heat - 2000-2200 kcal/kg; combustion speed - 20 mm/s; time ofburning - 42.5 s; volume of gaseous products - 600 l/kg; composition ofcombustion products: Cl₂, H₂O, H₂, MeO: combustion temperature - 2500°C.: ignition temperature - 500-700° C.; current for ignition ofpyrotechnic charge - 3-4 A. When such a source is used, all thecomponents of the well liquid pass into a vapor state as a result ofheating. The further from the heating element, the lower thetemperature, and consequently, there will be a zone where water andlight fractions pass into vapor, then there will be a zone where onlythe light fractions of oil pass into vapor, and finally, there will be azone where all the liquid in the well 1 is heated and its volumetricexpansion takes place.

[0083] An example is provided wherein the liquid is heated to atemperature higher than the boiling point of the heavy fractions.However, the heating temperature may be reduced to, for example, 100° C.In this case, there will not be a zone in which the heavy oil fractionspass into a vapor state. However, the other zones remain.

[0084] The next step is sealing the well 1 in the upper part above thepoint where the heating element 3 is positioned. In order to do this apacker 4 of any construction is used (FIGS. 2-5, 7). In the case ofinstant heating (during an explosion) of the liquid in the bottom-holezone of the well 1, it is advisable that the lower end face 5 of thepacker 4 (FIG. 7) be made in the form of a concave surface of the secondorder. Thus, a bottom-hole chamber 6 is formed in the bottom-hole zoneof the well 1, the upper part of chamber 6 being sealed.

[0085] Then heating the liquid in the bottom-hole chamber 6 is begun.Volumetric expansion of the liquid in the bottom-hole chamber 6 takesplace as a result of an increase of the temperature, and thispredetermines the formation of a flow of liquid towards the bottom holeof the well 1, and consequently, toward the productive formation (FIG.3). The higher the temperature to which the liquid in the bottom-holechamber 6 is heated, the more intensive will be its flow in thedirection toward the productive formation. After heating the liquid inthe bottom-hole chamber 6 stops, it is cooled in that chamber 6, whichreduces its volume (FIG. 5), as a result of which a reverse flow ofliquid is formed from the productive formation to the chamber 6. Theintensity of the reverse flow will depend on the speed of cooling theliquid in the bottom-hole chamber 6.

[0086] The speed of the reverse flow of liquid will be minimum in thecase where cooling is carried out in a natural manner, this making thestep simple to perform, since no equipment is needed. However, this stepmay be accomplished faster by carrying out forced cooling of the liquidin the bottom-hole chamber 6. In order to do this a special means, forexample a cooler 7, is preliminarily placed in the bottom-hole chamber 6below the packer 4 (FIG. 5). It is advisable that the cooler 7 and theheating element 3 be secured to the packer 4 from below and loweredsimultaneously into the well 1. The cooler 7 may operate in accordancewith any principle of action: mechanical, when cold water is fed fromthe surface of the well 1; electrical, when thermocouples are used forcooling; or chemical, using expanding gases. The more intense thecooling, the more intense the reverse flow of the liquid, and,consequently, the better the purification of the cracks and pores in thebottom-hole zone (filtration is improved). As a result, the inflow ofoil from the productive formation into the well 1 is increased. Theselection of the principle of cooling and corresponding special meanswill be determined by an economical approach and by the degree ofperfection of one or another method or set of equipment.

[0087] If the first step--heating the liquid in the bottom-hole chamber6--results in an improvement of the permeability of the bottom-holezone, since clogging the pores and cracks of the bottom-hole zone isreduced in view of the heating and melting of the paraffin, resin andasphaltenes deposited in the cracks and pores, the step relating tocooling the liquid in the bottom-hole chamber 6 creates rarefaction inthe bottom-hole zone, as a result of which intensive movement of theliquid from the productive formation to the well 1 is observed, whichpromotes purification of the part of the productive formation beingfiltered of deposits of particles, paraffins, resins, etc., and in somecases results in destruction of the rock of the bottom-hole zone of theproductive formation and formation of new cracks there. Cases are knownwhen after processing the bottom-hole zone with a reverse flow ofliquid, using implosion, the inflow of oil in oil producing wells 1increases several times. Sometimes wells 1, operated according to amechanized method, turn into spouting wells.

[0088] The next step is unsealing the bottom-hole zone of the well 1(FIG. 6), that is removal of the packer 4, after which the oil producingwell 1 may be exploited. The clogging products are removed from thebottom-hole zone of the well 1 after the latter is unsealed. This stepis carried out simultaneously with the oil production.

[0089] When the liquid in the bottom-hole chamber 6 is heated to atemperature of 80-96° C. (here and below consideration is given totemperature at normal pressure, since the pressure of the liquid in thebottom-hole zones in wells 1 is different and depends on the depth ofthe well 1, which changes from 800 to 4000 mn depending on the deposit),the light fractions of oil (gasoline, benzene, etc.) boil, water boilsat a temperature of 100° C., the heavy oil fractions boil attemperatures of 460-500° C. In the bottom-hole zone, the boiling pointof water and intermediate oil fractions increases depending on thepressure of the vertical column of the liquid in the well 1, remainingdifferent from each other.

[0090] If the light fractions of oil are heated to the boiling point,the partial pressure in the bottom-hole chamber 6 is created only byvapors of the light fractions of oil. If the temperature is increased,partial pressure occurs from the vapors of light fractions, water andheavy fractions of oil. Accordingly, the total pressure of the gases,which do not interact chemically with each other, is equal to the sum ofthe partial pressures of these gases (Dalton Law).

[0091] In order to determine the optimum temperature for heating theliquid in the bottom-hole chamber 6 it is necessary to know thecomposition of the liquid in the well 1. If the water encroachment ofthe latter is strong, then the heating may be limited to 100° C., takinginto account the pressure of the liquid in the well 1 (taking the depthof the well into account). If there are many light fractions in the oil,the heating temperature may be reduced, and to the contrary, where thereare a large number of heavy (viscous) fractions in the oil, it isadvisable that the temperature be raised to the boiling point of thoselatter fractions. At any heating temperature, the liquid, which has notpassed into vapor will increase in volume and thus promote the creationof a flow from the bottom-hole chamber 6 toward the productiveformation. However, this component will be less than the action of thepressure of the vapors of those or other fractions of oil and water.There will be a complex interaction of the vapors and expanding liquidin the bottom-hole zone. When pyrotechnic charges are used, zonalheating will be observed where, as the distance from the charge isincreased, the temperature will fall, and, consequently, a transition ofall the components of the well liquid together or separately to avaporous state will be observed.

[0092] The lower the temperature to which the liquid in the bottom-holechamber 6 is heated, the less the consumption of energy to perform thisoperation, but the effectiveness of the inflow of oil will be lower. Ifheating to high temperatures is used (when oils boil), then thetemperature near the source of heat will be maximum, i.e., boiling ofthe heavy and other fractions of oil near the heating source will beobserved, and at some distance the temperature will fall and only waterand light fractions of oil will boil.

[0093] It is most effective to use an explosion for realization of theproposed method for processing the bottom-hole zone (FIG. 4). In thiscase an increase of the pressure in the bottom-hole chamber 6 is ensuredand the liquid therein is heated to the maximum temperatures, i.e. thereis simultaneous action of the pressure on the pores in the bottom-holezone of the productive formation and temperature, reducing the viscosityof the oil. Taking into account that the upper part of the bottom-holezone of the well 1 is sealed, the effectiveness of the explosion in thatcase is at least two time more than the effectiveness of the methods forprocessing the bottom-hole zone of a well which are used at present,since all the combustion products are directed only downwards (adirected explosion takes place).

[0094] On the other hand the proposed method for processing a productiveformation in the bottom-hole zone of the well 1 includes thesimultaneous action of an explosive wave, a hydraulic fracture andtemperature, which result in the formation of additional cracks in thebottom-hole zone of the well 1, reduction of the viscosity of oilfractions and especially deposits, and also the reverse flow of liquidfrom the productive formation to the well 1, which promotes the removalof the deposits from the pores and cracks. In other words, the proposedmethod for processing the bottom-hole zone of the well 1 provides thepositive effects of known methods for processing a bottom-hole zone.Moreover, by sealing the upper part of the well 1, it is more effectivethan known methods, since direction of the explosion is ensured, andthis is at least two times more effective than a simple explosion in thewell 1.

[0095] Another advantage of the proposed method is the possibility ofcontrolling the degree to which the liquid in the bottom-hole zone isheated, this being dependent on the composition of the oil and thepercentage content of light and heavy fractions therein, and also theamount of water, which to a certain degree makes it possible to reducethe power consumed during this operation.

[0096] And finally, the proposed method provides for the preservation ofgeophysical cables and wire, arranged above the bottom-hole zone (abovethe packer 4).

[0097] Greater effectiveness may be achieved if a pressure generator 8is mounted at some distance from the bottom hole of the well (casing) 1(FIG. 8). In order to achieve this, a packer 4 is lowered into the well(casing) 1 (FIG. 8), using the suspension means (cable or pipe) 2. Thepacker 4 is fixed to the wall of the well 1 at some distance from thebottom, forming a bottom-hole chamber 6. Any method for fixing thepacker 4 to the wall of the well 1, like any construction of the packer4, may be used. The pressure generator 8 is secured in the lower part ofthe packer 4 on a hanger 9 at some distance from the bottom of the well1 and the end face of the packer 4. The pressure generator 8 may be madein the form of a tank with compressed gas or in the form of a packet ofexplosive.

[0098] Then the column of well liquid is divided by the gas fed from thetank or formed during an explosion of the explosive into two parts, oneof which (the lower) is directed toward the bottom-hole zone of the well1, the other (upper) through the packer 4-to the above-packer space ofthe well 1 (FIG. 9). The well liquid directed toward the bottom-holezone of the well 1 effects hydraulic fracturing in the bottom-hole zoneof the well 1, which predetermines expansion of the pores and cracks inthe zone of the productive formation surrounding the well 1, and alsoresults in the formation of new cracks. This, finally, will promote anincrease of the filtration of the formation liquid into the well 1,which results in an increase of the inflow of oil.

[0099] After the bottom-hole chamber 6 has been cleansed of the wellliquid (FIG. 10), the pressure of the gases therein, fed from the tankor formed as a result of an explosion, will fall, i.e. depression of thepressure will occur as a result of reduction of the temperature of thegases (heat through the wall of the well 1 as a result of the thermalconductivity of its walls will pass into the surrounding medium).

[0100] The next step is the step of filling the bottom-hole chamber 6with the formation liquid. Simultaneously with this, movement of theflow of well liquid positioned above the packer 4 into the bottom-holechamber 6 is closed (FIG. 11). In view of this the pressure of the gasesin the bottom-hole chamber 6 will be reduced, i.e. depression of thepressure will occur, and formation liquid will enter the bottom-holechamber 6. Wherewith, it will wash out the clogging products which arein the pores and cracks. Particles of earth, also to be found in thecracks and pores and hindering filtration of the formation liquid, willalso be washed out with the flow of well liquid.

[0101] The proposed complex action on the bottom-hole zone of the well 1(at first hydraulic fracturing, and then the action of pressuredepression) enhances the effectiveness of filtration of the formationliquid of the productive formation, which, finally, increases theproduction rate of oil in the well 1.

[0102] In order to realize the proposed method with use of an explosionas a step for the instantaneous increase of the temperature in thebottom-hole chamber 6, it is advisable to use a packer 4 with anyconstruction of the means for radial compaction, but in which the lowerend face 5 is made in the form of a concave surface of the second order.In other respects, the packer 4 units may be of any construction. Such aconcave surface may be made hemispheric or paraboloidal. These forms ofthe lower end face 5 of the packer 4 provide for direction of theexplosive wave along the longitudinal axis of the well 1 andsimultaneously ensure self-compaction of the packer 4 over the surfaceof the well 1, without creating stress concentrators in the packer 4. Inthe first case, production of the packer 4 is simplified, in thesecond - the effectiveness is enhanced, since the lower end face 5 ofthe packer 4 at the wall of the well 1 has greater length and moregradually passes to cylindrical.

[0103] In order to realize the proposed method with the use of anexplosion for cleansing the bottom-hole chamber 6 with division of thecolumn of well liquid, which is in this chamber 6, into two parts andtheir displacement to the productive formation and the above-packerspace of the well 1, it is necessary to use a special construction ofthe packer, which ensures the passage therethrough of a flow of wellliquid from the bottom-hole chamber 6 to the above-packer space of thewell 1 and prevents movement of the well liquid in the oppositedirection. A packer 4 with a flat lower end face is shown in FIGS. 8, 9;with a concave surface of the second order in FIGS. 10, 11. Bothconstructions satisfy the required conditions for passage of the wellliquid through the packer 4.

[0104] The packer 4 comprises a body 10 (FIGS. 8, 9) with a means 11 forradial compaction (a rubber bushing is shown in the FIG., which whenheated expands and creates tightness between the body 10 and the wall ofthe well [casing] 1). The packer 4 is lowered to the required depth by asuspension means 2 (FIG. 8), which may be a cable or pipe. The packer 4is made with channels (a channel) 12 (FIGS. 8-11) which connect its endfaces.

[0105] The channels 12 may be made parallel to the longitudinal axis ofthe packer 4 (FIGS. 8, 9) or inclined (FIGS. 10, 11), A back-pressurevalve 13, secured to the body 10 of the packer 4, is mounted in thechannels 12 or outside them as shown in FIGS. 8-11. The back-pressurevalve 13 is shown in the drawings in the form of a flat elastic plate,secured in the central part to the body 10 of the packer 4.

[0106] The principle of operation of the packer is as follows.

[0107] The packer 4 is lowered to the required depth and by any knownmethod is secured to the walls of the well 1 (FIG. 8). Well liquid is onboth sides of the end faces of the packer 4. A pressure generator 8 maybe suspended on a hanger 9 from the lower part of the packer 4. A tankwith compressed gas or a packet of explosive may be used as the pressuregenerator 8. The pressure generator 8 may be suspended on a specialcable passed through the packer 4. After the explosion (FIG. 9), underthe action of the explosion gases formed after the explosion of theexplosive or the gas in the tank, the upper part of the column of wellliquid in the bottom-hole chamber 6 will be displaced through thechannels 12 of the packer 4 into the above-chamber space of the well 1(FIG. 9). Wherein, the back-pressure valve 13 in the form of an elasticplate, deforming, passes the well liquid into the above-packer space.The lower part of the column of well liquid, which is in the bottom-holechamber 6, will be pressed toward the productive formation. After thebottom-hole chamber 6 is freed of the well liquid, the temperature ofthe gases in that chamber 6 will fall as a result of the transmission ofheat into the surrounding medium, and this will results in a reductionof the pressure of the gases in the bottom-hole chamber 6 - todepression of the pressure. Under the action of the column of wellliquid which is in the above-packer space of the well 1, the channels 12of the packer 4 are closed by the elastic force of the material of theelastic plate of the back-pressure valve 13. Reduction of the pressureof the gas will continue in the bottom-hole chamber 6, and after it hasfallen below the formation pressure, formation liquid will begin to gofrom the formation into the bottom-hole zone. The greater the depressionof the pressure in the bottom-hole zone, the more intensive will be theinflow of formation liquid into the bottom-hole chamber 6. Wherein, theclogging products and separate particles of earth, clogging the poresand cracks in the bottom-hole zone of the well 1, will be washed out.

[0108] It is advisable to use packers 4 in which control of fixation tothe walls of the well (casing) 1 is carried out by temperature action.Packers of such a construction are shown in FIGS. 12-15.

[0109] The packer 4, secured to the suspension means 2 in the form of acable (FIGS. 12, 13) or a pipe (FIGS. 14, 15), is installed in a well 1(FIGS. 14-15) or casing 1 (FIGS. 12-13). The packer 4 may be of anyconstruction. However, it, in accordance with the technical solution,should be provided with a temperature-action element 14 (this may beeither a heating element, for example, an electric spiral, or a coolingelement, for example, a thermocouple).

[0110] A packer with a structural element made of a material with shapememory is shown in FIG. 14. in this case, a diametral size increase iseffected by volumetric expansion of the material of the structuralelements (as described above) and by changing the shape of thestructural element of the packer 4, made of material with shape memory.Wherewith, the second factor by tens, and sometimes even hundreds, oftimes exceeds the first.

[0111] The packer 4 comprises an elastic cup-type seal 15 with a thrustwasher 16, clamps 17, 18 mounted above and below the cup-type seal 15, acylinder 19 with lobes 20 formed by slots 21, in the lower part of whichthe slots 21 pass into an opening 22. The cylinder 19 with lobes 20 ismade of material with shape memory, and therefore they serve as a drive(when moved apart), and together with the elastic cup-type seal 15 - assliding cheeks, a part of which closes the gap between the packer 4 andthe wall of the well (casing) 1. The cylinder 19 with lobes 20 and slots21 may be whole or consist of several sectors mounted in a circle. Thetemperature-action element 14 made in the form of a thermocouple shoulddesirably be mounted near the lobes 20 in order to cool them moreeffectively. Power to the temperature-action element 14 - thermocouplemay be effected from the surface along wires 23. The cylinder 19 is madeof a material with shape memory, for example, of a nickel-titanium alloy(for example, titanium nickelide NiTi with a content of 50% nickel and50% titanium). The specificity of these alloys is that if a sample madefrom them is given a certain shape by plastic deformation at atemperature higher than the temperature A_(E), and then cooled to atemperature below the temperature M_(E) and again deformed, destroyingthe former shape, then after heating the sample to a temperature abovethe temperature A_(B,) it will “remember” its original shape. Thetemperatures M_(B) and M_(E) are the beginning and end temperatures offorward martensite conversion, white A_(B) and A_(E) are respectivelythe beginning and end temperatures of reverse martensite conversion. Inrespect to a titanium nickelide NiTi alloy, the temperatures M_(B =)63°C., A_(B=)75° C. Addition of the alloying additions Fe and Co totitanium nickelide NiTi of a stoichiometric composition reduces thetemperature at which the shape is restored. The effect of the alloyingadditions on the shape restoration temperature is set forth, forexample, in the work by A.S. Tikhonov, A.P. Gerasimov, I.I. Prokhorov.Use of the shape memory effect in modem mechanical engineering,“Mashinostroenie,” Moscow, 1981, p. 80. Different alloys having theshape memory effect have their own physicomechanical parameters. Some ofthem are presented herebelow: the degree of restoration of the originalshape reaches 100%; the degree of reverse deformation reaches 10-20%;the pressure produced during heating reaches 500-700 MPa; the stressnecessary for preliminary deformation should not be more than 50-100 MPaThe temperature at which shape memory is manifested in alloys may changefrom −250° to 500° C., and the width of the temperature interval forrestoration of the shape - from 5 to 100° C., hysteresis from 2 to 80°C.

[0112] Here material on the base of titanium nickelide NiTi is indicatedas an example, this material having high mechanical strength andstability against lengthy temperature cycling, generating significantmechanical stresses when heated, having a significant specific workingcapacity.

[0113] The principle of operation of the packer and the method forfixing it in a well is as follows.

[0114] A packer 4 is lowered into a well (or casing) 1 on a suspensionmeans 2 in the form of a cable (FIGS. 12, 13) or pipe (FIGS. 14-15) tothe depth at which it should be fixed. Taking into account that as thedepth increases the temperature of the well liquid (this may be drillingmud or a mixture of oil and water) increases, the diametral size of thepacker 4 is selected so that at the temperature of the well liquid atthe depth of fixation, the diametral size of the packer 4 would be lessthan the diameter of the well 1. This may be achieved constructively,that is the parts of the packer 4 made with corresponding diameter, orthe packer 4 may be cooled, artificially reducing its diametral size.Then the packer 4 is subjected to temperature action (in this caseheating), which results in an increase of its diametral size (FIG. 13).If the packer 4 is made constructively with a diametral size less thanthe diameter of the well 1, the heating may be carried out with atemperature-action element 14, for example, an electric spiral, or byusing a pyrotechnic cartridge (not shown in the drawings). When apyrotechnic cartridge is used, the heating will be one-time, and thenthis temperature will be maintained by the temperature of the wellliquid. When an electric spiral is used, the packer 4 may be heated amultiple number of times and the maximum or optimum temperaturemaintained. This is especially important when the temperature of thewell liquid is less than the temperature of the martensite conversion ofthe shape memory alloy used. Wherewith, the heating is carried out froma power source mounted on the surface (not shown in the drawings). As aresult of the heating, a tightness is created between the surface of thecup-type seal 15 of the packer 4 and the surface of the wall of the well(casing) 1. In order to remove the packer 4 from the well 1, thetemperature load should be reduced (the packer 4 cooled), after which areduction of the volume of its structural elements occurs, the diametralsize of the packer 1 falls, and it may be extracted from the well 1. Thecooling may be natural (when the temperature of the well liquid is low)or artificial by using, for example, a thermocouple. In the latter case,the process may be controlled better, since it hardly depends at all onthe temperature of the well liquid.

[0115] The sequence of these operations is advisable when volumetricexpansion of the cup-type seal 15 of the packer 4 is used or it is madeof a material with a shape memory in which the temperature of forwardmartensite conversion is higher than the temperature of the well liquidat the depth of fixation of the packer 4. When executed in this manner,it is necessary to constantly consume power in order to ensure fixationof the packer 4 to the wall of a well (casing) 1.

[0116] It is advisable to cool the packer 4 prior to its installation inthe well 1 at the required depth (on the surface at the moment when itis to be lowered). Different means may be used on the surface in orderto accomplish this (for example, cover the packer with ice), in the well1 it is most advisable to use a thermocouple for this purpose. While thepacker 4 is cooling, its diametral size decreases and it becomessignificantly less than the diameter of the well 1, this simplifying theprocess of lowering the packer 4 into the well 1. Due to the action ofthe temperature of the well liquid, the packer 4 heats up, which resultsin an increase of its diametral size. If the temperature of the wellliquid at the depth at which the packer 4 is installed is known, it ispossible to calculate the initial diameter so that at the temperature ofthe well liquid, a tightness will appear between the side surface of thepacker 4 and the wall of the well 1. The force which appears during thetightening provides fixation of the packer 4 against the wall of thewell 1. In order to remove the packer 4 from the well 1, it is necessaryto cool it again (to carry out temperature relief). Wherewith, itsdiametral size becomes less than the diameter of the well 1, after whichit will be possible to extract the packer 4 from the well 1.

[0117] The constructions of a packer 4, which is heated, are shown inFIGS. 12 and 13, wherewith their fixation to the wall of the well 1 isachieved as a result of the volumetric expansion of the material duringheating. Using this principle, a packer 4 of any known construction maybe used, providing it with a heating element. In this case thereliability of fixation increases, since, in addition to the mechanicalchange of the diametral size of the packer 4 (for example, by displacingthe tapered surfaces in the packer according to USSR Inventor'sCertificate No. 252244), an additional tightness occurs as a result ofthe volumetric expansion of the material from which the elements of thepacker 4 are made.

[0118] A packer 4 is shown in FIGS. 14 and 15, in which material withshape memory is used. In this case, a diametral size increase iseffected as a result of the volumetric expansion of the material (asdescribed above) and a change of the shape of the packer 4.

[0119] The lobes 20 prior to being mounted in the packer 4 and afterbeing heated to a temperature exceeding temperature A_(E) are given theshape shown in FIG. 15, that is the lobes 20 are opened. Then they arecooled and deforming they together form the shape of a cylinder (FIG.14), i.e. the packer 4 is gathered when the lobes 20 have a flat shapein the longitudinal section, forming together a cylindrical surface. Thecylinder 19 together with the lobes 20 is positioned in an elasticcup-type seal 15, wherewith their contact surfaces may be glued. Theproduction of the elastic cup-type seal 15 together with the cylinder 19and its lobes 20 is possible, wherefore the rubber from which thecup-type seal 15 is made is boiled, the cylinder 19 and lobes 20 willserve as if armature. The problem of producing the elastic cup-type seal15 together with the cylinder 19 and its lobes 20 is solved concretelyduring the selection of the materials (what is meant is the temperatureto which the rubber of the cup-type seal 15 is heated and thetemperature A_(B)). An opening 22 is made in the cylinder 19 toeliminate the formation of cracks in the whole part of the cylinder 19.The cylinder 19 with lobes 20 and the cup-type seal 15 serve as thesliding cheeks.

[0120] Prior to the packer 4 being lowered, power is fed into the well 1along wires 23 to the temperature-action element 14 in the form of athermocouple serving as a cooler. The latter lowers the temperature ofthe structural elements of the packer 4, and therefore its diametraldimensions are somewhat reduced, while the lobes 20 retain a cylindricalshape (FIG. 14). The packer 4 is lowered into the well 1 to the requireddepth. Then the power to the thermocouple is turned off. The structuralelements of the packer 4 are heated under the effect of the temperatureof the well liquid. When the temperature rises above A_(B,) the lobes 20take on the shape shown in FIG. 15, which will be maintained as long asthe temperature will have an effect. If a more rapid rise of thetemperature is necessary, the packer 4 may be additionally provided witha pyrotechnic cartridge or electric spiral, which may be placed betweenthe suspension means (pipe) 2 and the cup-type seal 15 (not shown in theFIG.). The use of an additional supply of heat, for example, the heat ofan electric spiral, is justified in the case where the temperature ofthe well liquid is below the temperature A_(E), which occurs when thewells are not deep and in the case of use of material with shape memory,which has the values A_(B), A_(E), M_(B) and M_(E) greater than thetemperature of the well liquid. This, in turn, is advisable whenuniversal packers 4 are used which operate at all depths, wherewith atlarge depths, the temperature of the well liquid is sufficient forfixation, and when used at small depths - an additional supply of heatis necessary.

[0121] The open lobes 20 (FIG. 15) press the cup-type seal 15 againstthe surface of the wall of the well 1. Volumetric expansion of thestructural elements of the packer 4 as a result of the temperature willpromote tightness between the surfaces of the elastic cup-type seal 15and the wall of the well 1.

[0122] In order to extract the packer 4 from the well 1, it is necessaryto cool the lobes 20, feeding power to the thermocouple and providingtemperature relief to the packer 4. The lobes 20 converge in a radialdirection, the tightness between the surfaces of the elastic cup-typeseal 15 and the wall of the well 1 disappears, after which the packer 4may be extracted from the well 1, since its diametral size will besmall, less than the diametral size of the well 1.

[0123] The described operations, inherent to the method for fixing thepacker 4 to the wall of a well (casing) 1, in particular-temperatureaction on the packer 4, do not depend on its construction. Existingpackers 4 may be used, providing them with temperature-action elements14 (heaters and coolers of different principles of operation). In thatcase the reliability of their fixation is enhanced. It is advisable touse packers 4, the principle of action of which is based only on theaction of temperature. In that case a greater effect will be achieved,in particular: the construction is simplified; the reliability ofoperation is enhanced; control of the process of fixation issignificantly simplified, since it is provided by a special signal sentfrom the surface, which does not depend on the pressure of the wellliquid, the packer 4 may be fixed at any depth and its extraction fromthe well 1 is ensured.

Industrial Applicability

[0124] The proposed technical solution may be used most effectively inthe oil production industry: in order to increase the productivity of awell 1 by intensifying the flows of oil; to increase the oil recoveryfactor; during repair of wells; to cut off water-encroached formations,etc. The method for processing the productive formation in a bottom-holezone of a well, in accordance with the technical solution, is highlyeffective, relatively simple and convenient in use, since it is asingle-step method. The packer 4 for realization of the proposed methodis simple in production, ensures high reliability of fixation at anydepth of the well 1 and at different distances from its bottom-hole. Ascompared with known method for processing the productive formation it isat least two times more effective because the used explosion (heating)energy is directed to the bottom hole of the well 1, while in knownmethods more than 50% of the energy of an explosion goes upwards anddoes not act on the productive formation. The construction of the packerand the method for fixing it provide convenience of control due to theuse of a special signal consisting of heating and cooling packerelements to temperatures which are not present near the packer 4 in thewell liquid at the necessary depth of its fixation.

1. A method for processing a productive formation in a bottom-hole zoneof a well (1), comprising heating liquid in the bottom-hole zone andremoving clogging products from the bottom-hole zone, characterized inthat a temperature-action element (14) for heating the liquid to atemperature above the boiling point of its components is lowered intothe bottom-hole zone with use of a suspension means (2), a bottom-holechamber (6) is formed in the bottom-hole zone of the well (1), an upperportion of the chamber higher than the positioning of thetemperature-action element (14) is sealed by a packer (4), after beingheated the liquid is cooled, wherein heating the liquid and cooling itis carried out within the volume of the bottom-hole chamber (6), thenthe bottom-hole chamber (6) is unsealed by removal of the packer (4),after which the clogging products together with oil products are removedfrom the bottom-hole zone.
 2. A method according to claim 1,characterized in that the liquid in the bottom-hole chamber (6) isheated to a temperature above the boiling point of one of the light oilfractions, e.g., gasoline.
 3. A method according to claim 1,characterized in that the liquid in the bottom-hole chamber (6) isheated to a temperature above the boiling point of water.
 4. A methodaccording to claim 1, characterized in that the liquid in thebottom-hole chamber (6) is heated to a temperature above the boilingpoint of one of the heavy oil fractions, e.g., oils.
 5. A methodaccording to any one of claims 1-4, characterized in that the liquid inthe bottom-hole chamber (6) is heated instantly, e.g., by an explosion.6. A method according to any one of claims 1-5, characterized in thatcooling the liquid within the volume of the bottom-hole chamber (6) iscarried out in a forced manner with the use of, for example,thermocouples.
 7. A method according to any one of claims 1-5,characterized in that cooling the liquid within the volume of thebottom-hole chamber (6) is carried out in a forced manner, feeding coldwater from the surface.
 8. A method according to any one of claims 1-7,characterized in that a column of well liquid in the bottom-hole chamber(6) is divided into two parts by the packer (4) with at least onechannel (12) connecting its end faces and with a back-pressure valve(13), wherein one of the parts of the column of well liquid is directedtoward the bottom-hole zone of the well (1) for hydraulic fracturing,the other part is removed through the channel (12) of the packer (4),and movement of the well liquid through that channel (12) toward thebottom-hole chamber (6) from the above-packer space of the well isclosed.
 9. A method according to claim 8, characterized in that afterremoval of a part of the column of well liquid from the bottom-holechamber (6) through the packer (4), the pressure in the upper partthereof is reduced and simultaneously the bottom-hole chamber (6) isfilled with formation liquid.
 10. A packer (4) for processing aproductive formation in a bottom-hole zone of a well (1), comprising abody (10) with a means for radial compaction in the form of slidingcheeks, a cup-type seal (15) and a drive, and a suspension means (2),characterized in that its lower end face (5) is made in the form of aconcave surface of the second order.
 11. A packer (4) according to claim10, characterized in that the concave surface of the second order ismade hemispherical.
 12. A packer (4) according to claim 10,characterized in that the concave surface of the second order is madeparaboloidal.
 13. A packer (4) according to any one of claims 10-12,characterized in that in the case where a pressure generator (8) is usedin the well (1), including with an explosive, the packer (4) has atleast one channel (12) connecting its end faces, and a back-pressurevalve (13) is mounted with the possibility for passage of a flow of wellliquid from a bottom-hole chamber (6) through the channel (12) of thepacker (4) into above-packer space due to the action of pressuregenerator (8) gases, and for elimination of movement of the well liquidfrom the above-packer space into the bottom-hole chamber (6) withclosure of the channel (12) under the action of a column of liquid inthe above-packer space and depression in the bottom-hole chamber (6).14. A packer (4) according to claim 13, characterized in that theback-pressure valve (13) is made in the form of an elastic plate securedin its central part to the body of the packer (4).
 15. A packer (4)according to claim 13 or claim 14, characterized in that theback-pressure valve (13) is mounted in its channel (12).
 16. A packer(4) according to claim 15, characterized in that the channel (12)connecting its end faces is made in the body of the packer (4), and theback-pressure valve (13) is mounted from the side of its upper end face.17. A packer (4) according to any one of claims 10-16, characterized inthat its sliding cheeks are made in the form of a cylinder (19) withlongitudinal slots (21), ending with openings (27), wherein longitudinalparts of the cylinder ( 19) between tie slots (21 ) are made in the formof lobes (20) of a material with shape memory.
 18. A packer (4)according to claim 17, characterized in that it has a temperature-actionelement (14) in the form of a cooler to reduce the temperature of packer(4) elements when electric power is applied to the cooler.
 19. A packer(4) according to claim 18 characterized in that it is additionallyprovided with a heater, for example, a pyrotechnic cartridge or anelectric spiral.
 20. A method for fixing a packer (4) in a well (1),comprising lowering the packer (4) into the well (1) to a required depthincreasing diametral size of the packer (4) by changing the shape ofsliding cheeks during reverse martensite conversion of material withshape memory, deforming its cup-type seal (15) in a radial direction,subjecting the packer (4) to temperature action, different from thetemperature of the well liquid at the point of its installation,characterized in that the temperature action on the packer (4) iscarried out by reducing the temperature to a temperature below thetemperature of the well liquid at the point of installation of thepacker (4) prior to lowering the packer (4) to the required depth.
 21. Amethod according to claim
 20. characterized in that temperature reliefof the packer (4) is carried out after temperature action on the packer(4) at the point of its installation in the well (1) at the requireddepth.